1. Field of the Invention
The present invention relates to a frequency-analysis-type water level measuring method and a device therefor, and more particularly, to a method of measuring a water level using response signals indicating effects of impacts actuated during storage or flow of fluid in a container, and a device therefor.
The measuring device according to the present invention can be applied to an open container or a closed container, and to a container not only containing a fluid under normal temperature and pressure but also a container including a fluid under high temperature and pressure.
The device of the present invention adopts a principle that as the measuring device is immersed in a fluid deeply, the natural frequency of the device becomes lower, and as the depth thereof becomes shallower, that of the device becomes higher.
When an impact is applied to the device, response signal according to a water level appears different. The response signals are detected by a impact detecting sensor to analyze a frequency so that a frequency characteristic corresponding to the water level is shown. Accordingly, the water level can be measured by comparing the frequency characteristic with a previously input frequency characteristic according to water levels. Also, it is advantageous to detect the change of a water level in the container continuously by a trend of frequency characteristic measured only.
2. Description of the Related Art
In a conventional water level measuring device of a thermal transmission type used for the reactor in a nuclear power plant of a light-water type, there is discontinuity in measuring a water level which dominates accuracy of the water level measuring according to the number of thermal transmitting portions installed inside the measuring device. Thus, an operator in a power station cannot recognize the increase or decrease of the water level when the water level is positioned between the thermal transmitting portions.
When the water level measuring device of the frequency analysis type is installed in the reactor vessel of a nuclear power plant, the water level can be continuously measured so that the increase/decrease of the water level can always be recognized by the operator. Also, there is no delay effect of signals due to the sensor characteristic appearing in the water level measuring device of the thermal transmitting type.